324 



lives. No preference is shown for young or old leaves or for young or 

 mature trees. The whole of the tissue of the leaf segment, except 

 the midrib, is destroyed. Hence any poison applied must cover the 

 entire leaf, must be insoluble and adhesive, and also innocuous to the 

 foliage. Lead arsenate spray, 1| lb. of lead arsenate paste to 60 gals, 

 of water, to which has been added 10 lb. of slaked lime, has proved 

 most satisfactory. Spraying should be begun as soon as an attack is 

 observed. If the caterpillars are fully grown, it is useless to spray 

 until the next generation, since only a small portion would be affected. 

 The pupae should be collected and placed in a box, one side of which 

 is formed of wire netting of | inch mesh. The parasites, which emerge 

 at pupation, can thus escape to continue their attacks. The box must 

 be inaccessible to ants, which are liable to destroy the pupae. 



Richards (P. B.). Methods and Materials for the Control of Insect 

 Pests (Part I.). — Agric. Bull. Fed. Malay Slates, Kuala Limijmr, 

 iii, no. 3, December 1914, pp. 123-126. 



Important factors in the natural control of insects are the action 

 of climate, insectivorous birds, predatory insects, parasitic insects and 

 fungi, and the distribution of food-plants. An imported injurious insect 

 may find itself free from parasitic enemies and so increase rapidly if 

 suitable food-plants are available. Legislative measures which attempt 

 to control such pests apply generally to importation and transportation 

 of plants which may be infested. Cultural measures are important to 

 countries growing annual crops of the kind which do not lend themselves 

 readily to chemical or mechanical treatment. Rapid strides have been 

 made in recent years in the control of insects by chemical means, either 

 by spraying, dusting, or fumigation. Stomach poisons are appUed to 

 that part of the plant upon which the insect feeds, and are applicable 

 only to certain insects feeding on leaves or tissues on the outside of 

 the plant. Fumigation methods are effective against all kinds of 

 insects, but are especially valuable for those living in stored products. 

 Under mechanical measures are included various methods of trapping 

 the eggs, larvae, or adults. 



Richards (P. B.). Methods and Materials for the Control of Insect 

 Pests (Part II.). — Agric. Bull. Fed. Malay States, Kuala Lumjpur, 

 iii, no. 4, January 1915, pp. 145-154. [Received 3rd May 1915.] 



Direct injury caused by insects to plants is mainly inflicted in two 

 ways — either the tissues are eaten or the juices of the plant are sucked. 

 Since the majority live on the foliage, the most effective method of 

 eradication consists of poisoning the foUage upon which the insect is 

 feeding. Both vegetable and mineral stomach poisons are used, the 

 former consisting usually of solutions of alkaloids, the latter of arsenic 

 compounds. The substances may be applied either by dusting the 

 solid matter over the leaves or by spraying water in which it is sus- 

 pended by means of suitable apparatus. Of the arsenic compounds, 

 calcium arsenite is used in the proportion of 1 lb. to 100 or 150 galls, 

 of water ; the compound is insoluble in water, but the precipitate is 

 fine and remains in suspension. In this strength it is toxic to all 



